Nether portal teleport

So when i go through the nether portal in my house which is in a room that is 5x5 and 7 blocks high and for more detail the portal is against the wall. But when i go through it i end up in the nether and keep in mind this in on my hardcore world and this is also my only portal i have made in the world. So when i go to leave the nether instead of popping back in the portal that is in my house it makes a new portal that is about 50-60 blocks away. I even tried to break it and see if it was a one time thing but even after destroying it and trying again it keeps making the portal away from the house and putting me there whenever i leave the nether.